Any tips for setting up a smartphone with a macropad as mentioned? I like this idea but worry it introduces a lot of complexity for the non-smartphone literate population.

Regarding the cassette player, in the US the 'National Library Service for the Blind and Print Disabled' has a player with an excellent simple interface, using cartridges for each book: https://blog.library.in.gov/wp-content/uploads/2020/04/isl-t...